login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A002748 Sum of logarithmic numbers.
(Formerly M0923 N0347)
2
1, 2, 3, 26, 13, 1074, -1457, 61802, 7929, 4218722, -6385349, 934344762, -5065189307, 141111736466, 235257551943, 23219206152074, -97011062913167, 11887164842925762, -91890238533000461, 4819930221202545242, -14547510704199530499, 1184314832978574919922 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

J. M. Gandhi, On logarithmic numbers, Math. Student, 31 (1963), 73-83.

N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Table of n, a(n) for n=0..21.

J. M. Gandhi, On logarithmic numbers, Math. Student, 31 (1963), 73-83. [Annotated scanned copy]

Index entries for sequences related to logarithmic numbers

FORMULA

E.g.f.: F(x)/exp(x)/x where F(x) is o.g.f. for A000203(). - Vladeta Jovovic, Feb 09 2003

MAPLE

A002748 := proc(n) local f1, f2 ; f1 := add(numtheory[sigma](i)*x^(i-1), i=1..n+1) ; f2 := add((-x)^i/i!, i=0..n+1) ; n!*coeftayl(f1*f2, x=0, n) ; end: seq(A002748(n), n=0..25) ; # R. J. Mathar, Oct 22 2007

MATHEMATICA

f1[n_] := Sum[DivisorSigma[1, i]*x^(i-1), {i, 1, n+1}]; f2[n_] := Sum[(-x)^i/i!, {i, 0, n+1}] ; a[n_] := n!*SeriesCoefficient[f1[n]*f2[n], {x, 0, n}]; Table[a[n], {n, 0, 21}] (* Jean-Fran├žois Alcover, Jan 17 2014, after R. J. Mathar *)

CROSSREFS

Cf. A002750.

Sequence in context: A109586 A060371 A130975 * A056004 A032812 A099006

Adjacent sequences:  A002745 A002746 A002747 * A002749 A002750 A002751

KEYWORD

sign,easy

AUTHOR

N. J. A. Sloane

EXTENSIONS

More terms from Jeffrey Shallit

More terms from R. J. Mathar, Oct 22 2007

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 19 15:18 EDT 2019. Contains 327198 sequences. (Running on oeis4.)